Biomedical subjects

L Evans

Publications and source records attributed to L Evans.

At least 127 records · Page 7Linked to original sources

PubMed1989

Some biological aspects of panic disorder.

A review is made of the aetiology of panic disorders and of their relationship with agoraphobia. The paper confines itself to the review of evidence of the lactate induction of panic attacks and the response of panic disorder and agoraphobia to some antidepressants. It does not deal with genetic evidence or the dexamethasone suppression test. It is concluded that biological disturbance is probably a major causal factor of panic disorder, producing a physiological response but associated with some other factor.

Antidepressive Agents↗

PubMed1988

Separation of rabbit epiphyseal chondrocytes in various stages of differentiation.

Separation of fractions enriched in hypertrophic cells and proliferative cells has been achieved by density gradient centrifugation of cells from collagenase digests of rabbit epiphyseal cartilage. Concentrated suspensions of cells are centrifuged on a continuous Percoll density gradient. Hypertrophic cells remain in the upper part of the gradient and proliferative zone cells move to the lower regions. The resultant fractions show differences in mean cell diameter, alkaline phosphatase activity, morphology and synthetic activity in culture. Fractions rich in hypertrophic cells contain larger cells and more alkaline phosphatase activity than those enriched in proliferative cells. In culture the hypertrophic cells flatten as large irregular polygonal cells, whereas proliferative fractions form smaller spindle-shaped cells. In micromass culture hypertrophic fractions incorporate less 35S-sulphate and 14C-proline, and less tritiated thymidine than do proliferative fractions. These results suggest a general reduction in matrix and DNA synthesis with the attainment of the fully differentiated hypertrophic state, coincident with the expression of alkaline phosphatase activity and mineralisation of the cartilage matrix.

Animals↗

PubMed1988

Examination of some possible biases in double pair comparison estimates of safety belt effectiveness.

Biases in double pair comparison estimates of safety belt effectiveness due to two effects (noncoding of some surviving passengers, and driver/passenger impact during crashes) are investigated by calculating effectiveness from fatality frequencies assumed altered by the biases. Noncoding surviving right-front passengers does not affect estimates for drivers, but does overestimate slightly passenger effectiveness. Two biasing driver/passenger contact effects occur for right-side impacts--a "cushioning" effect (risk to unbelted driver is reduced by striking passenger rather than the vehicle interior) and a "missile" effect (passenger risk is increased by being struck by unrestrained driver). Cushioning and missile effects both reduce estimates; their combined effects could cause right-side impact effectiveness to be underestimated by as much as 20% (probably much less). Correcting for all effects increases the overall estimate from 42.6% to 43.2%. Thus, to the nearest percent, the result is still that if all presently unbelted drivers and right-front-seat passengers were to become wearers, fatalities to this group would decline by (43 +/- 3)%.

Accidents, Traffic↗

PubMed1988

Rear seat restraint system effectiveness in preventing fatalities.

Restraint system effectiveness for rear seat adult (16 years or older) car occupants is estimated by applying the double pair comparison method to Fatal Accident Reporting System (FARS) data for 1975 through 1985. As this data set contains information on fatal crashes only, the results apply exclusively to fatalities, and should not be generalized to other levels of injury. Rear seat occupants coded as using any restraint system are assumed to be using the lap belt only. Occupants in all four outboard seating positions (that is, driver and right front passenger, right and left rear passengers) serve as "other" occupants. Disaggregating the "other" occupant by restraint use generates six estimates of restraint system effectiveness for each of the two rear outboard positions. Insufficient data precluded estimating effectiveness for the center rear (or center front) positions, and also use of these occupants as "other" occupants. Average restraint system effectiveness for the two outboard rear seating positions is estimated as (18 +/- 9)%, where the error limit indicates one standard error. These estimates suggest that there is a 39 in 40 chance that rear lap belts reduce fatality likelihood, but a less than 1 in 10 chance that the reduction exceeds 30%.

Accidents, Traffic↗

PubMed1988

Helmet effectiveness in preventing motorcycle driver and passenger fatalities.

Helmet effectiveness in preventing fatalities to motorcycle drivers and passengers was determined by applying the double pair comparison method to the Fatal Accident Reporting System (FARS) data for 1975 through 1986. Motorcycles with a driver and a passenger, at least one of whom was killed, were used. In order to reduce as much as possible potentially confounding effects due to the dependence of survivability on sex and age, the analysis is confined to male drivers (there were insufficient female driver data), and to cases in which the driver and passenger age do not differ by more than three years. Motorcycle helmet effectiveness estimates are found to be relatively unaffected by performing the analyses in a number of ways different from that indicated above. It was found that helmets are (28 +/- 8)% effective in preventing fatalities to motorcycle riders (the error is one standard error), the effectiveness being similar for male and female passengers, and similar for drivers and passengers. An additional result found was that the fatality risk in the driver seat exceeds that in the passenger seat by (26 +/- 2)%. The 28% effectiveness found generates calculated fatality increases from repeal of mandatory helmet-wearing laws that are compatible with observed increases.

Accidents, Traffic↗

PubMed1988

Older driver involvement in fatal and severe traffic crashes.

The question of the risks older drivers face, and impose on others, was addressed by examining as a function of age and sex: (a) driver involvement in crashes in the same high severity range; (b) the threat drivers pose to pedestrians; and (c) the contribution of motor vehicle fatalities to overall mortality. National data files provide source information on traffic fatalities, population, number of licensed drivers, distance of travel, and mortality from all causes. Involvement rates in severe crashes are inferred from fatality data using recently published relations linking occupant survivability to age and sex. In no case among 14 measures examined did the value at the oldest age for which data were available (varied from source to source) exceed that for young drivers. Although some risks that drivers face may increase at older ages to levels above their minimum values, the increases are small compared to the substantial reductions in distances driven with increasing age; thus, reductions in mobility may be a more dominant correlate of aging than reductions in driving safety.

Accidents, Traffic↗

PubMed1988

Risk of fatality from physical trauma versus sex and age.

No large-scale epidemiologic study to investigate how sex and age affect fatal trauma risk from the same impact has been possible previously because large numbers of people are rarely subject to sufficiently similar major physical insults. This paper describes such a study, made possible by two recent developments: first, the availability of a large data file, the Fatal Accident Reporting System, which gives information on more than one third of a million people fatally injured in traffic crashes; second, a new technique, the double-pair comparison method, which, by focusing on vehicles containing two occupants, at least one of whom is killed, allows appropriate inferences to be made from such data. Fatality risk versus sex and age was determined for ten categories of vehicle occupants (unbelted car drivers, helmeted motorcycle passengers, etc.). Similar effects were found for different occupants, indicating that basic physiologic response (not confined to traffic fatalities) is being measured. It is found that fatality risk is about 25% greater for females than for similar aged males from about age 15 to 45 years. At younger and older ages males are more at risk. For both sexes, fatality risk is least at age 20 years. At age 70 it is about three times what it is at age 20.

Accidents, Traffic↗

PubMed1988

Seating position in cars and fatality risk.

Fatality risk in passenger cars according to seating position (front versus rear; left versus center or right) was examined using Fatal Accident Reporting System (FARS) data for 1975 through 1985. Comparing the fatality risk of unrestrained occupants matched in sex and age (within three years) revealed effects attributable to seating position, and not to occupant characteristics correlated with use of different seats. Fatality risk to drivers was the same as fatality risk to right front passengers to within 1 per cent; this was so for crashes in all directions and for frontal crashes. Fatality risk in rear seats was (26 +/- 2) per cent lower than in front seats, and lower in center compared to outboard seats by (22 +/- 4) per cent for front seats and (15 +/- 4) per cent for rear seats. The center rear seat was associated with the lowest fatality risk.

Accidents, Traffic↗

PubMed1988

Old age dependency in historical perspective.

In recent years much has been written about old age dependency and the need for greater emphasis on individual and familial responsibility for supporting elderly persons as opposed to state responsibility. We argue that old age dependency is not a new problem and that there was communal responsibility--as opposed to strictly privitized responsibility--for elderly persons in the past.

Aged↗

PubMed1988

Recombinant interferon alpha and gamma in combination as treatment for metastatic renal cell carcinoma.

Fifty-three patients with metastatic-renal cell carcinoma received treatment with combinations of recombinant alpha (rIFN-alpha-2a) and gamma (rIFN-gamma) interferons on three different treatment schedules. On treatment schedule A, 13 patients received i.m. rIFN-alpha-2a and rIFN-gamma simultaneously at a 1:1 ratio by dose units (2 X 10(6) U/m2), equivalent to a 1:10 ratio by protein weight. Results included severe constitutional symptoms in 62% of the patients and no partial remissions (PR) or complete remissions among 10 evaluable patients. On treatment schedule B, 25 patients received an i.m. injection of rIFN-alpha-2a and rIFN-gamma simultaneously at a 1:1 ratio by protein weight (2 X 10(6) U/m2 and 2 X 10(5) U/m2, respectively). This schedule was well tolerated, allowing a 25-50% increment in over 75% of the patients. Four patients (16%) achieved PR. On treatment schedule C, 15 patients received alternating weekly therapy: first rIFN-gamma (5 X 10(6) U/m2 daily for 7 days) followed by rIFN-alpha-2a (10 X 10(6) U/m2 daily for 7 days). One of 13 evaluable patients in treatment schedule C achieved an 80% tumor reduction and was rendered free of disease after the primary tumor was resected. Toxicity was similar in nature to that of rIFN-alpha-2a or rIFN-gamma separately. The toxicity of treatment schedule A suggested additive toxic effects. No distinct synergistic antitumor effect was observed.

Carcinoma, Renal Cell↗

PubMed1987

Serious or fatal driver injury rate versus car mass in head-on crashes between cars of similar mass.

This work was performed to determine relations between car mass and driver injuries (serious or fatal) when cars of similar mass crash into each other head-on. This type of crash is examined because it is considered similar in some respects to a barrier crash. Data from the United States Fatal Accident Reporting System (FARS) are used to examine driver fatality likelihood as a function of car mass when cars of similar mass crash into each other. Pedestrian fatalities involving cars of the same mass are used to estimate exposure. Two additional sources of data (State data from North Carolina and New York) are used to generate information on the number of drivers seriously injured or killed per police reported crash when cars of similar mass crash into each other. The present study finds that the likelihood of driver injury (fatal or serious) when cars of similar mass crash into each other increases with decreasing car mass, both for head-on crashes and for crashes in all directions. The study does not address possible mechanisms that might lead to such relations. All the data analyzed reveal a fairly consistent picture--a driver in a 900 kg car crashing head-on into another 900 kg car is about 2.0 times as likely to be seriously injured or killed as is a driver of a 1800 kg car crashing head-on into another 1800 kg car.

Accidents, Traffic↗

PubMed1987

Motorcyclist fatalities and the repeal of mandatory helmet wearing laws.

Previous studies had estimated that repeal of mandatory helmet wearing laws resulted in increases in the number of fatalities ranging from nearly 40% to essentially zero. This study was performed to determine more definitively the influence on motorcyclist fatalities of these repeals. After repeal, motorcyclist fatalities increased more in the states which repealed their laws than in those which did not in 24 cases out of 26, with the 95% confidence interval for the average effect being 25 +/- 6%. It is therefore concluded that repeals of mandatory helmet wearing laws for motorcyclists were followed by substantial increases in motorcyclist fatalities.

Accidents, Traffic↗

PubMed1987

Utility of fear survey schedule with Australian samples of anxiety disorder patients.

The Fear Survey Schedule (FSS) has been widely used in clinical settings for the assessment of anxiety disorders yet its reliability and validity is still in doubt. This paper reports the factor structure and the validity of the FSS using 130 agoraphobics with panic attacks, 98 phobics and 108 non-patient controls. The results show that a clear 6-factor solution can be derived from the FSS and this accounts for 46% of the variance. The 6 factors are (1) agoraphobia, (2) fear of small animals, (3) social anxiety, (4) negative social evaluation fears, (5) fear of bodily harm and (6) injury and fear of social interaction. The results of discriminate analysis show the following factors, that agoraphobics differ from phobics on agoraphobia, negative evaluations, fear of bodily harm and injury and social interaction fears. Compared with the non-patient group, agoraphobics differ in all factors except the small animal fear. The findings suggest that the FSS is a very robust and valid instrument for measuring fear in anxiety disorder patients.

Adolescent↗

PubMed1987

Plasma biogenic amine levels in agoraphobia with panic attacks.

Eight patients with agoraphobia and panic attacks as defined by DSMIII and 11 controls were included in this study which measured the circulating biogenic amine levels. The method of assay used a high performance liquid chromatograph with electrochemical detection. Measurement of dopamine, noradrenaline and adrenaline showed no differences between the groups. Levels of serotonin (5-HT) were significantly lower in the agoraphobic group. The authors discuss the implication of this finding.

Adult↗

PubMed1987

Fatality risk reduction from safety belt use.

This paper presents an overview of recent estimations of safety belt effectiveness obtained using a new technique--the double-pair comparison method. By effectiveness is meant the reduction, expressed as per cent, in fatalities to a presently unbelted population that would result if all of its members were to use belts, but not otherwise change their driving behavior. The double-pair comparison method is presented more simply, with less mathematical detail and rigor, than in earlier descriptions of it. The method is applied to determine the effectiveness of three-point lap/shoulder belts in preventing fatalities to drivers and right front passengers in passenger cars of model year 1974 or later, averaged over the distribution of crashes which occur in U.S. traffic. The method is then applied to investigate the dependence of effectiveness on a variety of vehicular, accident, roadway, and environmental factors. It is reported that if all presently unbelted drivers and right front passengers were to use the provided lap/shoulder belts, but not otherwise change their behavior, fatalities to this group would decline by (43 +/- 3)%. Safety belt effectiveness for drivers is higher in single-car crashes than in multiple-vehicle crashes, but does not depend much on a variety of other vehicle factors (for example, car size), accident factors (travel speed), roadway factors (posted speed limit), and environmental factors (light versus dark).

Accidents, Traffic↗

PubMed1987

Estimating fatality reductions from increased safety belt use.

Fatality reductions from increases in safety belt use are estimated taking into account that drivers who change from being nonusers to being users have lower accident involvement rates than the remaining nonusers, a process referred to as "selective recruitment." Analytical functions are derived which express expected fatality reductions in terms of changes in safety belt use rates from an initial rate. The function parameters are determined by requiring that computed average crash rates for nonusers be 53% higher than the rates for users, a recently determined empirical value. These functions show that, depending on the initial use rate and use rate increase, selective recruitment may increase or decrease expected fatality reductions. However, effects are relatively small, in no case exceeding +/- 5.3%.

Accidents, Traffic↗

PubMed1986

Hemolytic anemia and erythroleukemia, two distinct pathogenic effects of Friend MuLV: mapping of the effects to different regions of the viral genome.

Two different pathogenic effects of the Friend ecotropic murine leukemia virus (F-MuLV) were distinguished by serial examinations of hematocrits and reticulocyte counts of IRW mice inoculated as newborns. F-MuLV induced hemolytic anemia with increased levels of erythropoiesis, which was detectable as early as 13 days of age, whereas blocked erythroid differentiation, associated with erythroleukemia, was apparent only after 30 days of age. Using strains of Friend-MuLV with different virulences, we constructed recombinant viruses that allowed us to map the hemolytic effect and the ability to induce rapid erythroleukemia to different regions of the viral genome. Moreover, the ability of the virus to induce rapid erythroleukemia appeared to be independent of the presence of severe early hemolytic anemia.

Anemia, Hemolytic↗

PubMed1986

Sites of microtubule assembly and disassembly in the mitotic spindle.

We have microinjected biotinylated tubulin into mitotic fibroblast cells to identify the sites in the spindle at which new subunits are incorporated into microtubules (MTs). Labeled subunits were visualized in the electron microscope using an antibody to biotin followed by a secondary antibody coupled to colloidal gold. Astral MTs incorporate labeled subunits very rapidly by elongation of existing MTs and by new nucleation from the centrosome. At a slower rate, kinetochore MTs incorporate subunits at the kinetochore progressively during metaphase, suggesting a slow poleward flux of subunits in the kinetochore fiber. When cells injected in metaphase were examined in anaphase, a significant fraction of kinetochore MTs was unlabeled, suggesting that depolymerization had occurred at the kinetochore concomitant with chromosome to pole movement. The existence of opposite fluxes at the kinetochore during metaphase and anaphase suggests that two separate forces are responsible for chromosome congression and anaphase movement.

Anaphase↗